Mirofolliculina limnoriae

Protozoans

Mirofolliculina limnoriae is an epibiont of gribbles (Limnoria spp.), wood-boring isopods, with wide introduced and cryptogenic ranges.  It occurs on the back of the pleotelson of the gribble (Carlton 1979; Cohen and Carlton 1995).  Folliculnids are sessile, microscopic ciliates, which dwell within a bottle-shaped lorica, and project ciliated lobes for suspension-feeding.  Some morphological variation is seen in M. limnoriae found on different species of Limnoria, suggesting that this may be a species complex. Presumably, M. limnoriae has been introduced with L. quadripunctata and L. tripunctata. We consider this ciliate to be cryptogenic when associated with the circumboreal species L. lignorum and L. japonica, and in cryptogenic parts of the range of L. tripunctata.  Limnoria spp. were historically absent in San Francisco Bay, and southern California until 1870 -1875.  The exotic species L. quadridentata and L. tridentata were introduced by shipping ,at this time as indicated by damage to pilings, together with their symbionts. Heavy infestations of folliculinids can cause decreased feeding and growth in the gribbles.